1 - The iron should ALWAYS have a bit of fresh solder on it. Before
putting the tip in the holder dab solder on it, clean it on the
sponge, and dab solder again. At the very least do so before shutting
2 - Why? The iron tip will corrode and and become difficult to use.
Solder on the tip when it cools acts as a coating to protect the tip
from oxygen, and thus corrosion. Also, cleaning it first insures you
don't trap any gunk in there as it cools.
3 - Unless you have a REALLY GOOD REASON, don't turn the knob past 320
(straight up on the Hakkos). Excessive tip heat will damage it. Just
because the knob "goes to 11" does not mean that particular tip is
rated for it.
4 - Never, EVER use the Hakkos to melt plastic or
punch holes. I KILL you. Cleaning the tip after is a giant pain in the
ass, and they never work quite the same. We have some junk irons in
the drawer for this sort of thing.